Loop spreading mechanism for sewing machines



Nov. 12, 1957 c. R., NELSON LOOP SPREADING MECHANISM FOR SEWING MACHINES Filed July 15, 1955 4 Sheets-Sheet 1 0 m. 9 MN m mm m N Q WW WN n TN I .T I- J i AmW mm RN w 3 mw QN R m Hm? m|| II. II W -W lln /MW WNK. QIIWIN L f l kw 5 F \ll IININI Q N.\1 N H Q M h Q Q lg Ya/63% R-Nzison g o... 4 kllwi C. R. NELSON LOOP SPREADING MECHANISM FOR SEWING MACHINES Filed July 13, 1955 Nqv. 12, 1957 4 Sheets-Sheet 2 INVENTOR P. Nelson Q km Nov. 12, 1957 c. R. NELSON LOOP SPREADING macmmrsm FOR SEWING MACHINES Filed July 13, 1955 4 Sheets-Sheet 3 INVENTOR. Clarence P. Ne 250/1 ATTORNEYS Nov. 12, 1957 c. R. NELSON LOOP SPREADING MECHANISM FOR SEWING MACHINES Filed July 13, 1955 4 Sheets-Sheet 4 INV ENTORQ Clarence 1Q. Ne 750/7 BY WM M M /K ATTORNEYS United States Patent 2,812,735 Patented Nov. 12, 195 7 120%? EPREADING MECHANISM FOR SEWING MACHINES Clarence R. Nelson, Central Nyack, N. Y., assignor to Wiilcox & Gibbs Sewing Machine Company, New York, N. Y., a corporation of New York Application July 13, 1955, Serial No. 521,657 12 Claims. (Cl. 112-199) The present invention relates to an improved loop spreading mechanism for a sewing machine.

Heretofore, loop spreaders have been mounted on the throat plate of the machine or on the frame of the machine. When the throat plate was removed, the loop spreader was removed with it and when it was returned it was possible to put it back in a position in which the looper spreader was not connected to the drive mechanism of the machine and further where the spreaders were mounted on cylindrical rods carried by the frame it was a substantial operation to remove. the shafts and spreaders to afford access to the loopers and looper mechanism.

It is an object of the present invention to provide a loop spreading mechanism which is mounted on the frame of the sewing machine so as to be quickly moved to a retracted position from operative position when it is desired to have access to the loopers for threading and cleaning, can be adjusted readily as to extent of movement of the spreader needles and is provided with means whereby the spreader needles and the carriers therefor can be accurately positioned.

A feature of the invention resides in the. simplicity of construction and ease of operation and versatility in use.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the drawings in which:

Figure 1 shows a plan view of the sewing machine with the upper part of the machine removed to permit a clear showing of. the loop spreaders, loop mechanism and drives therefor.

Fig. 2 shows a side view of the structure shown in Fig. 1.

Fig. 3 is an end view of the device shown in Fig. 2 looking from the right of Fig. 2.

Fig. 4 is an end view of the bracket and mounting therefor in operative position looking from the left of Fig. 2.

Fig. 4A is a view similar to Fig. 4 showing the bracket in retracted position.

Fig. 5 is a sectional viewtaken alonglines 5--5 of Fig. 2.

Fig. 6 is a sectional view taken along lines 6-6 of Fig. 2. t

Fig. 7 is a sectional view" taken along lines 7-7 of Fig. 4.

Figs. 8, 9, 10. 111 and 12.show the sequentialoperation of the looper sewing needle and loop spreader during the formation of a stitch.

Figs. l3, 14, 15, 16 and 17 show a top view: of the looper needle, loop spreader needle and sewing needle in their various positions. corresponding to the positions shown in Figs. 8 to 12.

The invention is illustratedas applied to atwo needle.

chainstitch machine. For the sake of clarity the upper part of the machine including the throat plate and cloth plate has been removed so that the loop spreaders and their relation to the loopers and the sewing needles can be readily seen.

As shown in the drawings a frame 10 has a looper bracket 11 mounted thereon in which a looper shaft 12 carrying looper devices 13 is mounted for cooperative oscillation. and reciprocation with respect to the sewing needles 14. The shaft 12 is oscillated by means of the eccentric 15 on the main drive shaft 16 and a crank 17 connected to the shaft 12 and is reciprocated by the eccentric 13 on the main shaft and a bellcrank linkage 19 so that the looper carriers 20 mounted thereon and having loopers or looper needles 21 are moved through a predetermined cycle. While the number of looper carriers and sewing needles may vary in accordance with the sewing requirements, in the herein illustrated form of the invention there are shown two looper devices cooperating with a pair of sewing needles 14 carried by the usual needle bar 22 of the sewing machine with the loopers.

The present invention provides a novel loop spreading mechanism cooperating with the looper devices and sewing needles. This mechanism, as shown in the drawings, comprises a spreader bracket 23 pivotally mounted on the looper bracket 11. The spreader bracket has a spreader-needle support in the form of an elongate bar 24 mounted thereon for reciprocating movement in bearings 25. As shown in the drawing, the bearings are preferably U-shaped or saddle type which permits takeup for wear in the bar. mounted thereon and in whichspreading needles 27 areadjustably positioned. While the bracket maybe mounted in many ways, it is herein illustrated as pivotally supin Fig. 2, in which the spreader needles are so located as" to intercept the thread 28 carried by the looper needles to spread the loop of thread to permit the thread 29 carried by the sewing needle to be interlocked therewith.

The bracket is normally held in the operative position of Fig. 4 by a latch 30. Though the latch may take many forms, it is herein illustrated as a hook-type latch having a hook plate 31 mounted on a pivot 32 on the frame and provided with a downwardly facing notch 33 adaptedto receive a pin 34 on the bracket when the bracket is moved to operative position, the end of the plate having a cam surface 35 adapted to engage the pin and lift the latch against the action of a tension spring 36, the spring snapping the latch into holding relation with the pin when the notch and pin are aligned to securely hold the spreader bracketin place.

Theforward end of the latch is provided with a laterally projectingfingerpiece 37 by which the latch may be released should it be desired to move the bracket to the retracted position, as shown inFig. 4A, to afford ready access to the looper devices to clean or thread the same or to replace the looper needles. While the bracket may be moved toretracted position by springs, cams or other suitable means, it is. at present preferred to locate its center of gravity in such a manner that it will drop by gravity to retracted position.

A feature of the invention resides in'the novel spreaderneedle support whereby the carriers for the needles may This isaccomplished. by providing the support124 and spreader-needle carriers 26With at least one cooperating flat surface. In the illustrated form of the invention the suppoit is in the form of a channel bar 38-and the spreader- The bar has needle carriers 26- needle carriers have a channel 39 formed therein so that they engage and overlie the bottom and sides of the channel member as shown in Fig. 6. With the fiat sides of the support and carrier in engagement the carrier will be always properly located on the support for all adjusted positions therealong. Any suitable means may be pro vided for clamping the carrier in adjusted position. Preferably this is accomplished by providing a slot 40 in the base of the channel and providing a headed bolt 41 threaded in the carrier and extending through the channel so as to clamp the carrier in place.

Not only is the position of the carrier on the support adjustable, but the position of the spreader needle on the carrier is adjustable so as to vary the location of the spreader needle with respect to the carrier and/or the throat plate and to produce the desired angular position of the needle for various gauges of work. This is accomplished by providing the needle with a round shank 27a which is adapted to be inserted in a cylindrical socket 26a on the carrier, as shown in Fig. 6, and locked in place by a set screw 42. This construction also permits ready replacement of damaged spreader needles.

The support and spreader needles carried thereby are reciprocated transversely of the looper in timed relation to the movement of the looper by means of a slotted collar 43 on the looper shaft cooperating with a lever 44 pivotally mounted on the spreader bracket 23 by an adjustable pivot pin 45. The lever has one end connected to a roller 46 cooperating with a slot 43a in the collar to be drven thereby and the other end connected to the support bar so that as the looper shaft is reciprocated the spreader-needle support will be reciprocated by the lever. The pivot pin for the lever is adjustably mounted in a vertical slot 23b in the bracket and extends through a slot 44a in the lever, as shown in Fig. 5, so that by adjusting the pivot pin toward or away from the looper shaft the extent of movement of the support can be reg ulated as desired.

Should it be desired to adjust the position of the needles in operative position with respect to the looper mechanism, the present invention provides an adjustable eccentric 32a on the pivot for the latch as is clearly shown in Fig. 7. By rotating the pivot pin 32 and locking it in adjusted position by lock nut 47, the position of the latch can be moved rearwardly or forwardly the desired amount to properly position and hold the spreader bracket and the spreader needles with respect to the looper and sewing needles.

Since the spreader needles must move through a predetermined precise distance, it is at present preferred to provide an adjusting means whereby any side play on the part of the spreader bracket is eliminated. In the il- -1ustrated form of the invention this comprises a bolt 48 threaded in the looper bracket with its end in position to engage the spreader bracket. A lock nut 49 locks the bolt in adjusted position. In adjusting the bolt care should be taken, however, not to produce any binding action which would interfere with the movement of the spreader bracket to retracted position.

Figs. 8 to 12 and related Figs. 13 to 17 show diagrammatically the relative positions of the looper needles, sewing needles and spreader needles during a cycle. As will be noted from Figs. 13 to 17, the looper needle moves in a tear drop type of pattern, as shown by the dotted line. The arrows in these figures indicate the direction of movement of the spreader needle, looper and sewing needle as the spreader needle intercepts the thread carried by the looper needle as shown in Fig. 13, moves it laterally as shown in Fig. 14 to provide a pocket for the entrance of the sewing needle, releases the loop as shown in Fig. 15 and moves back to starting position as shown in the upper dotted position of Fig. 16 in preparation for the next movement of the looper as the sewing needle moves to complete the sewing cycle.

From the foregoing it will be seen that the present invention provides a novel loop spreading means in which the spreader needles are independently mounted for adjustment with respect to the looper and are carried by a carrier which can readily move from operative position to a retracted position to facilitate cleaning, threading, and replacement of the looper or spreader needles, all without substantial dismantling of the sewing machine. The device of the present invention is easy to install and operate and has great versatility in that it can be readily adapted to the various requirements for different sewing operations.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having a spreader needle support thereon provided with a flat surface, a spreader-needle carrier having a spreader needle adjustably mounted therein clamped to said flat surface so as to properly position the needle carried thereby to cooperate with thread carried by the loopers to spread the thread to form a loop to receive the sewing needle, and releasable latch means on the frame engaging and holding the bracket in operative position, said bracket and spreader needles carried thereby moving to retracted position upon release of the latch whereby free access to the loopers is provided.

2. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having a spreader needle support mounted thereon for reciprocation transversely of the loopers and provided with a flat surface, a spreaderneedle carrier having a spreader needle adjustably mounted therein clamped to said fiat surface so as to properly position the needle carried thereby to cooperate with the thread carried by the loopers to spread the loop to receive the sewing needle, means for reciprocating the support in timed relation to the operation of the looper and sewing needle, and releasable latch means on the frame engaging and holding the bracket in operative position, said bracket andspreader needles carried thereby moving to retracted position upon release of the latch whereby free access to the loopers is provided.

3. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising an elongate spreader-needle support consisting of a U-shaped channel member carried by the frame for reciprocation transversely of the loopers, means for reciprocating the support in timed relation to the operation of the loopers and sewing needles, said U-shaped channel member having an elongate slot in the bottom of the channel, spreader-needle carriers having spreader needles mounted thereon, said carriers having a recess therein providing portions overlying and engaging the bottom and sides of the channel member to be properly positioned thereby and having clamping means extending through said slot to secure the carriers in adjusted position thereon.

4. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising an elongate spreader-needle support consisting of a U-shaped channel member carried by the frame for reciprocation transversely of the loopers, means for reciprocating the support in timed relation to the operation of the loopers and sewing needles; said U- shaped channel member having an elongate slot in the bottom of the channel, spreader-needle carriers having spreader-needle recesses therein, said carriers having a recess therein providing portions overlying and engaging the bottom and sides of the channel to be properly positioned thereby and having clamping means extending through. said .slot to lseeuretthe carriers inadjusted position thereon, spreader needles having cylindrical shanks mounted in said recesses for adjustment of the needles longitudinally and angularly with respect to the recesses, and clamp screw means threaded into the carriers to hold the needles in adjusted position.

5. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotallymounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having spreader needles thereon cooperating with the thread carried by the loopers to spread the loop to receive the sewing needle, and releasable latch means on the frame engaging and holding the bracket in operative position, said bracket and spreader needles carried thereby moving to retracted position upon release of the latch whereby free access to the loopers is provided.

6. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an opera tive position and a retracted position with respect to said loopers and having spreader needles thereon cooperating with the thread carried by the loopers to spread the loop to receive the sewing needle, and releasable latch means on the frame comprising a pivoted hook plate having a notch engaging a portion of the bracket to hold the bracket in operative position, said bracket and spreader needles carried thereby moving to retracted position upon release of the hook plate from the bracket whereby free access to the loopers is provided.

7. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having spreader needles thereon cooperating with the thread carried by the loopers to spread the loop to receive the sewing needle, and releasable latch means on the frame comprising a pivoted hook plate having a notch engaging a pin on the bracket to hold the bracket in operative position and a fingerpiece projecting laterally from the plate whereby the latch can be moved to released position whereupon said bracket and spreader needles carried thereby move to retracted position and free access to the loopers is provided.

8. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having spreader needles thereon cooperating with the thread carried by the loopers to spread the loop to receive the sewing needle, and releasable latch means on the frame comprising a pivoted hook plate having a downwardly facing notch adjacent the end thereof engaging a pin on the bracket to hold the bracket in operative position, said bracket and spreader needles carried thereby moving to retracted position upon release of the hook plate from the pin whereby free access to the loopers is provided, the end of the plate having a pin-engaging cam surface to raise the latch and permit the pin to snap into the notch when the bracket is returned to operative position.

9. Loop spreader means for a sewing machine having a frame and cooperating loopers and sewing needles thereon comprising a bracket pivotally mounted on the frame for movement relative to said loopers between an operative position and a retracted position with respect to said loopers and having spreader needles thereon cooperating with the thread carried. by the loopers to spread theloop to receive the sewing needle, releasable latch means on the frame engaging and holding the bracket in operative position, said latch being pivotally mounted on the frame by means of an adjustable pivot whereby the position of the latch and operative position of the bracket and spreader needles carried thereby can be adjusted toward or away from the loopers, said bracket and spreader needles carried thereby moving to retracted position upon release of the latch whereby free access to the loopers is provided.

10. Loop spreader means for a sewing machine having a, frame, loopers; carriedby an oscillating and reciprocating looper shaft mounted on the frame and cooperating with sewing needles to produce a sewing operation and comprising a bracket pivotally mounted on the looper shaft to move from an operative to a retracted position, means for releasably holding the bracket in operative position, an elongate spreader-needle support carried by the bracket for reciprocation transversely of the loopers, and means reciprocating the support in timed relation to the operation of the loopers and sewing needles, said means comprising a lever pivoted to the bracket and having one end connected to the support and the other end connected to the looper shaft to be moved thereby by the reciprocation of the looper shaft, said support having at least one flat face, spreader-needle carriers adjustably carried by the support and having spreader needles thereon, said carriers having a flat face cooperating with the flat face on the support to properly position the carrier thereon.

11. Loop spreader means for a sewing machine having a frame, loopers mounted on an oscillating and reciprocating looper shaft and sewing needles cooperating with said loopers to produce a sewing operation and comprising a bracket mounted on the looper shaft to freely pivot thereon between an operative position and a retracted position, a pivoted latch means releasably holding the bracket in operative position, an elongate, channelshaped spreader-needle support carried by the bracket for reciprocation transversely of the loopers, means reciprocating the support in timed relation to the operation of the loopers and sewing needles, said means comprising a lever mounted on the bracket by an adjustable pivot and having one end connected to the support and the other end connected to a slotted collar on the looper shaft to be moved thereby by the reciprocation of the looper shaft, said support having a slot in its bottom and fiat faces on the bottom and sides thereof, spreaderneedle carriers adjustably carried by the support and having spreader needles adjustably mounted thereon, said carriers having fiat faces cooperating with the fiat faces on the support to properly position the carrier thereon, and clamping screw means passing through the slot in the bottom and threaded into the carriers to hold the carriers in adjusted position on the support.

12. Loop spreader means for a sewing machine having a frame, loopers mounted on an oscillating and reciprocating looper shaft and sewing needles cooperating with said loopers to produce a sewing operation and comprising a bracket mounted on the looper shaft to freely pivot thereon between an operative position and a retracted position, a pivoted latch means releasably holding the bracket in operative position, an elongate, channel-shaped spreader-needle support carried by the bracket for reciprocation transversely of the loopers, means reciprocating the support in timed relation to the operation of the loopers and sewing needles, said means comprising a lever mounted on the bracket by an adjustable pivot and having one end connected to the support and the other end connected to a slotted collar on the looper shaft to be moved thereby by the reciprocation of the looper shaft, said support having a slot in its bottom and flat faces on the bottom and sides thereof, spreader nee carriers adjustably carried by the support and havi 7 spreader needles adjustably mounted thereon, said carriers having flat faces cooperating with the flat faces on the support to properly position the carrier thereon, and clamping screw means passing through the slot in the bottom and threaded into the carriers to hold the carriers in adjusted position on the support, said pivoted latch means comprising a pivoted hook plate having a downwardly facing notch engaging a pin on the bracket to hold the bracket in operative position and a fingerpiece projecting from the plate whereby the latch can be moved to released position whereupon said bracket and spreader needles carried thereby move to retracted position and free access to the loopers is provided, the

end of the plate having a pin-engaging cam surface to raise the latch and permit the pin to snap into the notch when the bracket is returned to operative position.

References Cited in the file of this patent UNITED STATES PATENTS 

